There is another compactron that one could use, and that is the 7689...if you where lucky enough to find one. The 7689 12BA base pin-out is a bit different than the 6C10 12BQ base, but the tube itself is a triple triode 12AX7 with all the best features.
I should think that if you rewired the base, and put one in, you should never have to change it, even the standard 6C10 seems to last for a very long time.
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according to the guy selling one, they won't fit in a standard 12 pin base / / / http://rover.ebay.com/rover/1/711-5...0001&campid=5338148343&icep_item=152963599949